IKKβ Regulates VEGF Expression and Is a Potential Therapeutic Target for Ovarian Cancer as an Antiangiogenic Treatment

Recent advances and future directions on small molecule VEGFR inhibitors in oncological conditions

"A journey of mixed emotions" is a quote that best describes the progress chart of vascular endothelial growth factor receptor (VEGFR) inhibitors as cancer therapeutics in the last decade. Exhilarated with the Food and Drug Administration (FDA) approvals of numerous VEGFR inhibitors coupled with the annoyance of encountering the complications associated with their use, drug discovery enthusiasts are on their toes with an unswerving determination to enhance the rate of translation of VEGFR inhibitors from preclinical to clinical stage. The recently crafted armory of VEGFR inhibitors is a testament to their growing dominance over other antiangiogenic therapies for cancer treatment. This review perspicuously underscores the earnest attempts of the researchers to extract the antiproliferative potential of VEGFR inhibitors through the design of mechanistically diverse structural assemblages. Moreover, this review encompasses sections on structural/molecular properties and physiological functions of VEGFR, FDA-approved VEGFR inhibitors, and hurdles restricting the activity range/clinical applicability of VEGFR targeting antitumor agents. In addition, tactics to overcome the limitations of VEGFR inhibitors are discussed. A clear-cut viewpoint transmitted through this compilation can provide practical directions to push the cart of VEGFR inhibitors to advanced-stage clinical investigations in diverse malignancies.

Genome Editing of Pik3cd Impedes Abnormal Retinal Angiogenesis

Abnormal angiogenesis is associated with myriad human diseases, including proliferative diabetic retinopathy (PDR). Signaling transduction through phosphoinositide 3-kinases (PI3Ks) plays a critical role in angiogenesis. Herein, we showed that p110δ, the catalytic subunit of PI3Kδ, was highly expressed in pathological retinal vascular endothelial cells (ECs) in a mouse model of oxygen-induced retinopathy (OIR) and in fibrovascular membranes from patients with PDR. To explore novel intervention with PI3Kδ expression, we developed a recombinant dual adeno-associated viral (rAAV) system for delivering CRISPR/Cas9 in which Streptococcus pyogenes (Sp) Cas9 expression was driven by an endothelial specific promoter of the intercellular adhesion molecule 2 (pICAM2) to edit genomic Pik3cd, the gene encoding p110δ. We then demonstrated that infection of cultured mouse vascular ECs with the dual rAAV1s of rAAV1-pICAM2-SpCas9 and rAAV1-SpGuide targeting genomic Pik3cd resulted in 80% DNA insertion/deletion in the locus of genomic Pik3cd and 70% depletion of p110δ expression. Furthermore, we showed that in the mouse model of OIR editing retinal Pik3cd with the dual rAAV1s resulted in not only a significant decrease in p110δ expression, and Akt activation, but also a dramatic reduction in pathological retinal angiogenesis. These findings reveal that Pik3cd editing is a novel approach to treating abnormal retinal angiogenesis.

The multiple combination of Paclitaxel, Ramucirumab and Elacridar reverses the paclitaxel-mediated resistance in gastric cancer cell lines

Introduction

Paclitaxel (PTX) interferes with microtubule architecture by binding to β-tubulin, thereby blocking progression at the G2/M phase and inducing apoptosis. This study aimed to investigate molecular processes underlying PTX-mediated resistance in gastric cancer (GC) cells.

Methods

PTX-mediated resistance involves many processes, and in this work some of the factors involved in the resistance mechanism were identified by comparing two GC lines with PTX induced resistance to their sensitive counterparts.

Results

Thus, the key feature of PTX-resistant cells was the overexpression of pro-angiogenic factors such as VEGFA, VEGFC, and Ang2, known to support tumor cell growth. A second relevant change detected in PTX-resistant lines was the elevated level of TUBβIII, a tubulin isoform that opposes microtubule stabilization. A third identified factor contributing to PTX-resistance was P-glycoprotein (P-gp), a transporter responsible for chemotherapy efflux from the cells, highly expressed in PTX-resistant lines.

Discussion

These findings were in line with a greater sensitivity of resistant cells to treatment with both Ramucirumab and Elacridar. Ramucirumab significantly reduced the expression of angiogenic molecules and TUBβIII, while Elacridar restored the access of chemotherapy, recovering its anti-mitotic and pro-apoptotic effects. Finally, this study highlighted the role played by exosomes in spreading factors responsible for resistance in the tumor microenvironment.

Research Progress in Prognostic Factors and Biomarkers of Ovarian Cancer

Ovarian cancer is a serious threat to women's health; its early diagnosis rate is low and prone to metastasis and recurrence. The current conventional treatment for ovarian cancer is a combination of platinum and paclitaxel chemotherapy based on surgery. The recurrence and progression of ovarian cancer with poor prognosis is a major challenge in treatment. With rapid advances in technology, understanding of the molecular pathways involved in ovarian cancer recurrence and progression has increased, biomarker-guided treatment options can greatly improve the prognosis of patients. This review systematically discusses and summarizes existing and new information on prognostic factors and biomarkers of ovarian cancer, which is expected to improve the clinical management of patients and lead to effective personalized treatment.

Dll1+ quiescent tumor stem cells drive chemoresistance in breast cancer through NF-κB survival pathway

Development of chemoresistance in breast cancer patients greatly increases mortality. Thus, understanding mechanisms underlying breast cancer resistance to chemotherapy is of paramount importance to overcome this clinical challenge. Although activated Notch receptors have been associated with chemoresistance in cancer, the specific Notch ligands and their molecular mechanisms leading to chemoresistance in breast cancer remain elusive. Using conditional knockout and reporter mouse models, we demonstrate that tumor cells expressing the Notch ligand Dll1 is important for tumor growth and metastasis and bear similarities to tumor-initiating cancer cells (TICs) in breast cancer. RNA-seq and ATAC-seq using reporter models and patient data demonstrated that NF-κB activation is downstream of Dll1 and is associated with a chemoresistant phenotype. Finally, pharmacological blocking of Dll1 or NF-κB pathway completely sensitizes Dll1+ tumors to chemotherapy, highlighting therapeutic avenues for chemotherapy resistant breast cancer patients in the near future.

New Antimicrobial Bioactivity against Multidrug-Resistant Gram-Positive Bacteria of Kinase Inhibitor IMD0354

Multidrug-resistant pathogens pose a serious threat to human health. For decades, the antibiotic vancomycin has been a potent option when treating Gram-positive multidrug-resistant infections. Nonetheless, in recent decades, we have begun to see an increase in vancomycin-resistant bacteria. Here, we show that the nuclear factor-kappa B (NF-κB) inhibitor N-[3,5-Bis(trifluoromethyl)phenyl]-5-chloro-2-hydroxybenzamide (IMD0354) was identified as a positive hit through a Caenorhabditis elegans–methicillin-resistant Staphylococcus aureus (MRSA) infection screen. IMD0354 was a potent bacteriostatic drug capable of working at a minimal inhibitory concentration (MIC) as low as 0.06 µg/mL against various vancomycin-resistant strains. Interestingly, IMD0354 showed no hemolytic activity at concentrations as high as 16 µg/mL and is minimally toxic to C. elegans in vivo with 90% survival up to 64 µg/mL. In addition, we demonstrated that IMD0354′s mechanism of action at high concentrations is membrane permeabilization. Lastly, we found that IMD0354 is able to inhibit vancomycin-resistant Staphylococcus aureus (VRSA) initial cell attachment and biofilm formation at sub-MIC levels and above. Our work highlights that the NF-κB inhibitor IMD0354 has promising potential as a lead compound and an antimicrobial therapeutic candidate capable of combating multidrug-resistant bacteria.

Exploring the potential of engineered exosomes as delivery systems for tumor-suppressor microRNA replacement therapy in ovarian cancer

MicroRNA (miRNA) plays a pivotal role in cancer biology. Therefore, tumor suppressor (TS) miRNAs are an attractive target for cancer therapy. However, clinical trials have failed due to the difficulties in miRNA delivery, warranting the development of a novel drug delivery system (DDS). Exosomes are stable in circulation and selectively picked up by cancer cells, indicating that they can serve as a miRNA carrier. The aim of this study was to explore the possibility of exosomes as a carrier for miRNA replacement therapy for ovarian cancer (OC). First, exosomes were purified from primary-cultured omental fibroblasts of OC patients. miR-199a-3p was selected as a TS miRNA, and the synthesized miR-199a-3p was loaded into exosomes by electroporation. Treatment with miR199a-3p-loaded-exosomes (miR-199a-3p-Exo) drastically increased miR-199a-3p expression level in OC cell lines (CaOV3; 8592-, SKOV3; 67188-, and OVCAR3; 2280-fold). miR-199a-3p-Exo suppressed c-Met expression, a direct target of miR-199a-3p, and thereby inhibited cell proliferation and invasion. In a xenograft study, miR-199a-3p-Exo also drastically inhibited peritoneal dissemination in OC mice model, and diminished c-Met expression, ERK phosphorylation, and MMP2 expression in tumors. These results suggest that miRNA replacement therapy using exosomes shows promise for treatment of OC. Given that omental fibroblasts can be obtained from most OC patients, patient-derived exosomes can be utilized as a DDS for future molecular-targeted therapies.

IKKβ Inhibitor IMD-0354 Attenuates Radiation Damage in Whole-body X-Irradiated Mice

Nuclear factor-kappa B (NF-κB) transcription factor plays a critical role in regulating radiation-induced inflammatory and immune responses. Intracellular reactive oxygen species generation induces the activation of NF-κB via the inhibitor of κB (IκB) kinase (IKK) complex signaling. Previous studies have reported that the inhibition of IKK-driven NF-κB activation offers a therapeutic strategy for managing inflammatory disorders and various cancers, but it has additionally been reported that treatment targeting NF-κB also shows a radioprotective effect. IMD-0354 is an IKKβ inhibitor that blocks IκBα phosphorylation in the NF-κB pathway. This compound is known to exert anti-inflammatory and antitumor effects, but its radioprotective effects are unclear. Therefore, in the present study, we examined whether or not IMD-0354 has a mitigative effect on radiation-induced damages in mice. IMD-0354 was dissolved in soybean oil and subcutaneously administered to C57BL/6J Jcl mice for 3 consecutive days after 7 Gy of whole-body X-irradiation. The survival rate on day 30 and the NF-κB p65 and IκBα in bone marrow and spleen cells based on flow cytometry were assessed. IMD-0354 administration significantly suppressed the lethality induced by whole-body X-irradiation, and the survival rate increased by 83%. The NF-κB p65 and IκBα in bone marrow and spleen cells were significantly lower in IMD-0354-treated mice than in irradiated mice, suggesting that the IKKβ inhibitor IMD-0354 exerts a radiomitigative effect by suppressing the NF-κB.

Ablation of Immunoproteasome β5i Subunit Suppresses Hypertensive Retinopathy by Blocking ATRAP Degradation in Mice

Inflammation is associated with retinal diseases. Our recent data demonstrate that immunoproteasome catalytic subunit β2i contributes to angiotensin II (Ang II)-induced retinopathy in mice. Here, we investigated the role of another catalytic subunit β5i in regulating retinopathy and its underlying mechanisms. We induced a murine model of retinopathy by infusing Ang II (3,000 ng/kg/min) for 3 weeks into wild-type (WT) mice, β5i-knockout (KO) mice, or WT mice injected with either adenovirus-expressing β5i (Ad-β5i) or angiotensin II type 1 receptor (AT1R)-associated protein (Ad-ATRAP), which inhibits AT1R. The β5i expression and chymotrypsin-like activity were most significantly elevated in Ang II-infused retinas and serum from patients with hypertensive retinopathy. Moreover, Ang II infusion-induced retinopathy was markedly attenuated in β5i-KO mice but aggravated in Ad-β5i-injected mice. Accordingly, β5i KO markedly restored Ang II-induced downregulation of ATRAP and activation of AT1R downstream mediators, which was further enhanced in Ad-β5i-injected mice. Interestingly, overexpression of ATRAP significantly abrogated Ang II-induced retinopathy in Ad-β5i-injected mice. This study found that β5i promoted Ang II-induced retinopathy by promoting ATRAP degradation and activation of AT1R-mediated signals.

NF-κB Signaling in Ovarian Cancer

The NF-κB signaling pathway is a master and commander in ovarian cancer (OC) that promotes chemoresistance, cancer stem cell maintenance, metastasis and immune evasion. Many signaling pathways are dysregulated in OC and can activate NF-κB signaling through canonical or non-canonical pathways which have both overlapping and distinct roles in tumor progression. The activation of canonical NF-κB signaling has been well established for anti-apoptotic and immunomodulatory functions in response to the tumor microenvironment and the non-canonical pathway in cancer stem cell maintenance and tumor re-initiation. NF-κB activity in OC cells helps to create an immune-evasive environment and to attract infiltrating immune cells with tumor-promoting phenotypes, which in turn, drive constitutive NF-κB activation in OC cells to promote cell survival and metastasis. For these reasons, NF-κB is an attractive target in OC, but current strategies are limited and broad inhibition of this major signaling pathway in normal physiological and immunological functions may produce unwanted side effects. There are some promising pre-clinical outcomes from developing research to target and inhibit NF-κB only in the tumor-reinitiating cancer cell population of OC and concurrently activate canonical NF-κB signaling in immune cells to promote anti-tumor immunity.

Selective targeting of tumor cells and tumor associated macrophages separately by twin-like core-shell nanoparticles for enhanced tumor-localized chemoimmunotherapy

Tumor associated macrophage (TAM)-based immunotherapy has been presented as a promising strategy in cancer therapy. The combination of TAM-based immunotherapy with sorafenib (SF) could be conceivably quite more effective in hepatocellular carcinoma (HCC) treatment. A co-delivery system was superior in improving the co-accumulation of two drugs in tumor tissues for chemoimmunotherapy, while in the case of selective targeting of separated cells such as tumor cells and immune cells, a novel targeted co-delivery strategy was badly required. In this study, twin-like core-shell nanoparticles (TCN) were developed for synchronous biodistribution and separated cell targeting delivery of SF and TAM re-polarization agents IMD-0354 to cancer cells and TAM to enhance tumor-localized chemoimmunotherapy, respectively. First of all, SF loaded cationic lipid-based nanoparticles (SF-CLN) and mannose-modified IMD-0354 loaded cationic lipid-based nanoparticles (M-IMD-CLN) were prepared, respectively. SF on the surface of SF-CLN and mannose on the M-IMD-CLN were regarded as targeting ligands for selective targeting delivery of SF-CLN and M-IMD-CLN to cancer cells and TAM separately. Then, pH-responsive charge reversal polymer O-carboxymethyl-chitosan (CMCS) was coated on the SF-CLN and M-IMD-CLN to obtain twin-like CMCS/SF-CLN and CMCS/M-IMD-CLN, respectively. The results of cellular uptake assay on Hepa1-6 cells and RAW 264.7 cells in vitro, respectively, as well as the results of tumor tissue distribution of SF and IMD-0354 in vivo suggested that CMCS/SF-CLN and CMCS/M-IMD-CLN exhibited similar properties in vitro and synchronous biodistribution in vivo, and were efficient at separated cell targeting delivery. What's more, the results of antitumor efficiency in vivo and phenotype analysis of TAM in tumor tissues proved that CMCS/SF-CLN and CMCS/M-IMD-CLN exhibited superior synergistic antitumor efficacy and M2-type TAM polarization ability compared with SF treatment in Hepa1-6 tumor bearing mice. Consequently, TCN which was the combination of co-administration and nano-drug delivery systems has great potential to be used in tumor-localized chemoimmunotherapy in clinics.

IKKβ targeting reduces KRAS-induced lung cancer angiogenesis in vitro and in vivo: A potential anti-angiogenic therapeutic target

OBJECTIVES

The ability of tumor cells to drive angiogenesis is an important cancer hallmark that positively correlates with metastatic potential and poor prognosis. Therefore, targeting angiogenesis is a rational therapeutic approach and dissecting proangiogenic pathways is important, particularly for malignancies driven by oncogenic KRAS, which are widespread and lack effective targeted therapies. Based on published studies showing that oncogenic RAS promotes angiogenesis by upregulating the proangiogenic NF-κB target genes IL-8 and VEGF, that NF-κB activation by KRAS requires the IKKβ kinase, and that targeting IKKβ reduces KRAS-induced lung tumor growth in vivo, but has limited effects on cell growth in vitro, we hypothesized that IKKβ targeting would reduce lung tumor growth by inhibiting KRAS-induced angiogenesis.

MATERIALS AND METHODS

To test this hypothesis, we targeted IKKβ in KRAS-mutant lung cancer cell lines either by siRNA-mediated transfection or by treatment with Compound A (CmpdA), a highly specific IKKβ inhibitor, and used in vitro and in vivo assays to evaluate angiogenesis.

RESULTS AND CONCLUSIONS

Both pharmacological and siRNA-mediated IKKβ targeting in lung cells reduced expression and secretion of NF-κB-regulated proangiogenic factors IL-8 and VEGF. Moreover, conditioned media from IKKβ-targeted lung cells reduced human umbilical vein endothelial cell (HUVEC) migration, invasion and tube formation in vitro. Furthermore, siRNA-mediated IKKβ inhibition reduced xenograft tumor growth and vascularity in vivo. Finally, IKKβ inhibition also affects endothelial cell function in a cancer-independent manner, as IKKβ inhibition reduced pathological retinal angiogenesis in a mouse model of oxygen-induced retinopathy. Taken together, these results provide a novel mechanistic understanding of how the IKKβ pathway affects human lung tumorigenesis, indicating that IKKβ promotes KRAS-induced angiogenesis both by cancer cell-intrinsic and cancer cell-independent mechanisms, which strongly suggests IKKβ inhibition as a promising antiangiogenic approach to be explored for KRAS-induced lung cancer therapy.

RIPK4 promotes bladder urothelial carcinoma cell aggressiveness by upregulating VEGF-A through the NF-κB pathway

BACKGROUND

Constitutively activated nuclear factor kappa B (NF-κB) signalling plays vital roles in bladder urothelial carcinoma (BC) progression. We investigate the effect of receptor-interacting protein kinase 4 (RIPK4) on NF-κB activation and BC progression.

METHODS

The expression of RIPK4 was examined in 25 cryopreserved paired bladder samples and 112 paraffin BC specimens. In vivo and in vitro assays were performed to validate effect of RIPK4 on NF-κB pathway-mediated BC progression.

RESULTS

High expression of RIPK4 was observed in BC tissues and was an independent predictor for poor overall survival. Up or downregulating the expression of RIPK4 enhanced or inhibited, respectively, the migration and invasion of BC cells in vitro and in vivo. Mechanistically, RIPK4 promoted K63-linked polyubiquitination of tumour necrosis factor receptor-associated factor 2 (TRAF2), receptor-interacting protein (RIP) and NF-κB essential modulator (NEMO). RIPK4 also promoted nuclear localisation of NF-κB-p65, and maintained activation of NF-κB substantially, leading to upregulation of VEGF-A, ultimately promoting BC cell aggressiveness.

CONCLUSIONS

Our data highlighted the molecular aetiology and clinical significance of RIPK4 in BC: upregulation of RIPK4 contributes to NF-κB activation, and upregulates VEGF-A, and BC progression. Targeting RIPK4 might represent a new therapeutic strategy to improve survival for patients with BC.

The immunoproteasome subunit LMP10 mediates angiotensin II-induced retinopathy in mice

Inflammation has been implicated in a variety of retinal diseases. The immunoproteasome plays a critical role in controlling inflammatory responses, but whether activation of immunoproteasome contributes to angiotensin II (Ang II)-induced retinopathy remains unclear. Hypertensive retinopathy (HR) was induced by infusion of Ang II (3000 ng/kg/min) in wild-type (WT) and immunoproteasome subunit LMP10 knockout (KO) mice for 3 weeks. Changes in retinal morphology, vascular permeability, superoxide production and inflammation were examined by pathological staining. Our results showed that immunoproteasome subunit LMP10 expression and its trypsin-like activity were significantly upregulated in the retinas and serum of Ang II-infused mice and in the serum from patients with hypertensive retinopathy. Moreover, Ang II-infused WT mice showed an increase in the central retinal thickness, vascular permeability, reactive oxygen species (ROS) production and inflammation compared with saline controls, and these effects were significantly attenuated in LMP10 KO mice, but were aggravated in mice intravitreally injected with rAAV2-LMP10. Interestingly, administration of IKKβ specific inhibitor IMD-0354 remarkably blocked an Ang II-induced increase in vascular permeability, oxidative stress and inflammation during retinopathy. Mechanistically, Ang II-induced upregulation of LMP10 promoted PTEN degradation and activation of AKT/IKK signaling, which induced IkBα phosphorylation and subsequent degradation ultimately leading to activation of NF-kB target genes in retinopathy. Therefore, this study provided novel evidence demonstrating that LMP10 is a positive regulator of NF-kB signaling, which contributes to Ang II-induced retinopathy. Strategies for inhibiting LMP10 or IKKβ activity in the eye could serve as a novel therapeutic target for treating hypertensive retinopathy.

Inflammatory related gene IKKα, IKKβ, IKKγ cooperates to determine liver cancer stem cells progression by altering telomere via heterochromatin protein 1-HOTAIR axis

Cancer stem cells are associated with tumor recurrence. IKK is a protein kinase that is composed of IKKα, IKKβ, IKKγ. Herein, we demonstrate that IKKα plus IKKβ promoted and IKKγ inhibited liver cancer stem cell growth in vitro and in vivo. Mechanistically, IKKα plus IKKβ enhanced and IKKγ inhibited the interplay among HP1α, HP1β and HP1γ that competes for the interaction among HP1α, SUZ12, HEZ2. Therefore, IKKα plus IKKβ inhibited and IKKγ enhanced the activity of H3K27 methyltransferase SUZ12 and EZH2, which methylates H3K27 immediately sites on HOTAIR promoter region. Therefore, IKKα plus IKKβ increased and IKKγ decreased the HOTAIR expression. Strikingly, IKKα plus IKKβ decreases and IKKγ increases the HP1α interplays with DNA methyltransferase DNMT3b, which increases or decreases TERRA promoter DNA methylation. Thus IKKα plus IKKβ reduces and IKKγ increases to recruit TRF1 and RNA polymerase II deposition and elongation on the TERRA promoter locus, which increases or decreases TERRA expression. Furthermore, IKKα plus IKKβ decreases/increases and IKKγ increases/decreases the interplay between TERT and TRRRA/between TERT and TREC. Ultimately, IKKα plus IKKβ increases and IKKγ decreases the telomerase activity. On the other hand, at the telomere locus, IKKα plus IKKβ increases/drcreases and IKKγ decreases/increases TRF2, POT1, pPOT1, Exo1, pExo1, SNM1B, pSNM1B/CST-AAF binding, which keep active telomere regulatory genes and poised for telomere length. Strikingly, HOTAIR is required for IKKα plus IKKβ and IKKγ to control telomerase activity and telomere length. These observations suggest that HOTAIR operates the action of IKKα, IKKβ, IKKγ in liver cancer stem cells. This study provides a novel basis to elucidate the oncogenic action of IKKα, IKKβ, IKKγ and prompts that IKKα, IKKβ, IKKγ cooperate to HOTAR to be used as a novel therapeutic targets for liver cancer.

Selective IKK2 inhibitor IMD0354 disrupts NF-κB signaling to suppress corneal inflammation and angiogenesis

Corneal neovascularization is a sight-threatening condition caused by angiogenesis in the normally avascular cornea. Neovascularization of the cornea is often associated with an inflammatory response, thus targeting VEGF-A alone yields only a limited efficacy. The NF-κB signaling pathway plays important roles in inflammation and angiogenesis. Here, we study consequences of the inhibition of NF-κB activation through selective blockade of the IKK complex IκB kinase β (IKK2) using the compound IMD0354, focusing on the effects of inflammation and pathological angiogenesis in the cornea. In vitro, IMD0354 treatment diminished HUVEC migration and tube formation without an increase in cell death and arrested rat aortic ring sprouting. In HUVEC, the IMD0354 treatment caused a dose-dependent reduction in VEGF-A expression, suppressed TNFα-stimulated expression of chemokines CCL2 and CXCL5, and diminished actin filament fibers and cell filopodia formation. In developing zebrafish embryos, IMD0354 treatment reduced expression of Vegf-a and disrupted retinal angiogenesis. In inflammation-induced angiogenesis in the rat cornea, systemic selective IKK2 inhibition decreased inflammatory cell invasion, suppressed CCL2, CXCL5, Cxcr2, and TNF-α expression and exhibited anti-angiogenic effects such as reduced limbal vessel dilation, reduced VEGF-A expression and reduced angiogenic sprouting, without noticeable toxic effect. In summary, targeting NF-κB by selective IKK2 inhibition dampened the inflammatory and angiogenic responses in vivo by modulating the endothelial cell expression profile and motility, thus indicating an important role of NF-κB signaling in the development of pathologic corneal neovascularization.

Prognostic value of GRIM-19, NF-κB and IKK2 in patients with high-grade serous ovarian cancer

AIMS

High grade serous carcinoma (HGSC) is an aggressive tumour, and most patients relapse after treatment, acquiring resistance to platinum-based chemotherapy. One of the resistance mechanisms proposed is apoptosis evasion triggered by drug-related cytotoxic effect in the cell. In this context, this study aims to evaluate the protein expression of GRIM-19, NF-κB and IKK2, their association with chemotherapy response and to determine their prognostic values in HGSC.

METHODS

GRIM-19, NF-κB and IKK2 expression was evaluated by immunohistochemistry (IHC) in 71 patients with HGSC selected between 2003 and 2013, whose underwent primary debulking surgery with complete cytoreduction. Protein expression was analyzed in relation to platinum response groups, tumour progression, clinicopathological data and survival.

RESULTS

Positive IKK2 expression was related to resistance (p = 0.011), shorter disease-free survival (p = 0.001) and overall survival (p = 0.026) and was also a risk factor for relapse (p = 0.002) and death (p = 0.032). The association between IKK2 and NF-κB positivity predicted a subgroup with shorter overall survival (p = 0.004), disease-free survival (p = 0.003) and resistance to platinum-based chemotherapy (p = 0.036). NF-κB positivity was associated with worse overall survival (p = 0.005) and disease-free survival (p = 0.027) and was a positive predictor for relapse (p = 0.032) and death (p = 0.008). Higher expression of GRIM-19 was associated with higher disease-free survival (p = 0.039) and was a negative predictor for relapse (p = 0.046).

CONCLUSIONS

GRIM-19 is a potential predictor of prognosis and disease recurrence in HGSC. IKK2 and NF-κB are related to poor prognosis and are potential predictors of response to platinum-based chemotherapy in HGSC. IHC analyses of GRIM19, IKK2 and NF-κB may be important in the attempt to provide prognostic values for relapse and response to treatment in patients with HGSC.

The Novel IκB Kinase β Inhibitor, IMD-0560, Has Potent Therapeutic Efficacy in Ovarian Cancer Xenograft Model Mice

OBJECTIVE

Aberrant activation of nuclear factor-kappa β (NF-κB) signaling has been correlated with poor outcome among patients with ovarian cancer. Although the therapeutic potential of NF-κB pathway disruption in cancers has been extensively studied, most classical NF-κB inhibitors are poorly selective, exhibit off-target effects, and have failed to be applied in clinical use. IMD-0560, N-[2,5-bis (trifluoromethyl) phenyl]-5-bromo-2-hydroxybenzamide, is a novel low-molecular-weight compound that selectively inhibits the IκB kinase complex and works as an inhibitor of NF-κB signaling. The aim of this study was to assess the therapeutic potential of IMD-0560 against ovarian cancer in vitro and in vivo.

METHODS

NF-κB activity (phosphorylation) was determined in 9 ovarian cancer cell lines and the inhibitory effect of IMD-0560 on NF-κB activation was analyzed by Western blotting. Cell viability, cell cycle, vascular endothelial growth factor (VEGF) expression, and angiogenesis were assessed in vitro to evaluate the effect of IMD-0560 on ovarian cancer cells. In vivo efficacy of IMD-0560 was also investigated using an ovarian cancer xenograft mouse model.

RESULTS

The NF-κB signaling pathway was constitutively activated in 8 of 9 ovarian cancer cell lines. IMD-0560 inhibited NF-κB activation and suppressed ovarian cancer cell proliferation by inducing G1 phase arrest. IMD-0560 decreased VEGF secretion from cancer cells and inhibited the tube formation of human umbilical vein endothelial cells. IMD-0560 significantly inhibited peritoneal metastasis and prolonged the survival in an ovarian cancer xenograft mice model. Immunohistochemical staining of excised tumors revealed that IMD-0560 suppressed VEGF expression, tumor angiogenesis, and cancer cell proliferation.

CONCLUSIONS

IMD-0560 showed promising therapeutic efficacy against ovarian cancer xenograft mice by inducing cell cycle arrest and suppressing VEGF production from cancer cells. IMD-0560 may be a potential future option in regimens for the treatment of ovarian cancer.

Exosomes Promote Ovarian Cancer Cell Invasion through Transfer of CD44 to Peritoneal Mesothelial Cells

Epithelial ovarian cancer (EOC) cells metastasize within the peritoneal cavity and directly encounter human peritoneal mesothelial cells (HPMC) as the initial step of metastasis. The contact between ovarian cancer cells and the single layer of mesothelial cells involves direct communications that modulate cancer progression but the mechanisms are unclear. One candidate mediating cell-cell communications is exosomes, 30-100 nm membrane vesicles of endocytic origin, through the cell-cell transfer of proteins, mRNAs, or microRNAs. Therefore, the goal was to mechanistically characterize how EOC-derived exosomes modulate metastasis. Exosomes from ovarian cancer cells were fluorescently labeled and cocultured with HPMCs which internalized the exosomes. Upon exosome uptake, HPMCs underwent a change in cellular morphology to a mesenchymal, spindle phenotype. CD44, a cell surface glycoprotein, was found to be enriched in the cancer cell-derived exosomes, transferred, and internalized to HPMCs, leading to high levels of CD44 in HPMCs. This increased CD44 expression in HPMCs promoted cancer invasion by inducing the HPMCs to secrete MMP9 and by cleaning the mesothelial barrier for improved cancer cell invasion. When CD44 expression was knocked down in cancer cells, exosomes had fewer effects on HPMCs. The inhibition of exosome release from cancer cells blocked CD44 internalization in HPMCs and suppressed ovarian cancer invasion. In ovarian cancer omental metastasis, positive CD44 expression was observed in those mesothelial cells that directly interacted with cancer cells, whereas CD44 expression was negative in the mesothelial cells remote from the invading edge. This study indicates that ovarian cancer-derived exosomes transfer CD44 to HPMCs, facilitating cancer invasion.

IMPLICATIONS

Mechanistic insight from the current study suggests that therapeutic targeting of exosomes may be beneficial in treating ovarian cancer. Mol Cancer Res; 15(1); 78-92. ©2016 AACR.

IKK inhibition increases bortezomib effectiveness in ovarian cancer

Ovarian cancer is associated with increased expression of the pro-angiogenic chemokine interleukin-8 (IL-8, CXCL8), which induces tumor cell proliferation, angiogenesis, and metastasis. Even though bortezomib (BZ) has shown remarkable anti-tumor activity in hematological malignancies, it has been less effective in ovarian cancer; however, the mechanisms are not understood. We have recently shown that BZ unexpectedly induces the expression of IL-8 in ovarian cancer cells in vitro, by IκB kinase (IKK)-dependent mechanism. Here, we tested the hypothesis that IKK inhibition reduces the IL-8 production and increases BZ effectiveness in reducing ovarian tumor growth in vivo. Our results demonstrate that the combination of BZ and the IKK inhibitor Bay 117085 significantly reduces the growth of ovarian tumor xenografts in nude mice when compared to either drug alone. Mice treated with the BZ/Bay 117085 combination exhibit smallest tumors, and lowest levels of IL-8. Furthermore, the reduced tumor growth in the combination group is associated with decreased tumor levels of S536P-p65 NFκB and its decreased recruitment to IL-8 promoter in tumor tissues. These data provide the first in vivo evidence that combining BZ with IKK inhibitor is effective, and suggest that using IKK inhibitors may increase BZ effectiveness in ovarian cancer treatment.